loading page

Comparison of Compact Liquid Crystal-based Phase Shifting Topologies for Reconfigurable Intelligent Surfaces
  • +3
  • Robin Neuder ,
  • Tom Burmeister ,
  • Dongwei Wang ,
  • Martin Schüssler ,
  • Rolf Jakoby ,
  • Alejandro Jiménez-Sáez
Robin Neuder
Technical University Darmstadt

Corresponding Author:[email protected]

Author Profile
Tom Burmeister
Author Profile
Dongwei Wang
Author Profile
Martin Schüssler
Author Profile
Rolf Jakoby
Author Profile
Alejandro Jiménez-Sáez
Author Profile


This paper presents and compares two promising approaches for realizing liquid crystal (LC)-based phase shifting topologies for Reconfigurable Intelligent Surfaces (RIS). Main requirements for the phase shifters include high Figure of Merit (FoM), compact size, low response times and constant group delay. The first approach is based on defective ground structure inverted microstrip lines (DGS-IMSL) and shows high FoM above 74 °/dB between 25 and 30 GHz. In addition, it promises low response times due to its thin 4.6 µm LC layer and features moderate physical length below 0.45 λ0. However, it is limited by a non-constant group delay. The second approach, the bandpass inverted microstrip line (BP-IMSL), has a lower FoM of approximately 26 °/dB between 28 to 30 GHz with a thicker LC layer of 20 µm. Nevertheless, a shorter physical size below 0.25 λ0 is accomplished and potential for a flat group delay is given.
19 Sep 2023Published in 2023 53rd European Microwave Conference (EuMC). 10.23919/EuMC58039.2023.10290199